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Electrostatic Nonplanar Positron-Acoustic shock Waves in superthermal Electron-Positron-Ion Plasmas

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Communications in Theoretical Physics 2015年第6期63卷 754-760页

作者： m.J.Uddin m.s.alam A.A.mamun Department of Physics Jahangirnagar University

The basic properties of the nonlinear propagation of the nonplanar(cylindrical and spherical) positronacoustic(PA) shock waves(sHWs) in an unmagnetized electron-positron-ion(e-p-i) plasma containing immobile positive ions,mobile cold positrons,and superthermal(kappa distributed) hot positrons and electrons are investigated both analytically and *** modified Burgers equation(mBE) is derived by using the reductive perturbation *** basic features of PA sHWs are significantly modified by the cold positron kinematic viscosity(η),superthermal parameter of electrons(κ_e),superthermal parameter of hot positrons(κ_p),the ratio of the electron temperature to hot positron temperature(σ),the ratio of the electron number density to cold positron number density(μ_e),and the ratio of the hot positron number density to cold positron number density(μ_(ph)).This study could be useful to identify the basic properties of nonlinear electrostatic disturbances in dissipative space and laboratory plasmas.

关键词：等离子体静电干扰正电子非平面电子数密度非线性传播声波电子温度

Diversity and structural composition of species in dipterocarp forests:a study from Fasiakhali Wildlife sanctuary, Bangladesh

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Journal of Forestry Research 2018年第5期29卷 1241-1249页

作者： s.C.Das m.s.alam m.A.Hossain Institute of Forestry and Environmental sciences University of Chittagong

Fasiakhali Wildlife sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan（Dipterocarpus spp.）*** present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 *** forest is low in plant diversity as represented by shannon–Wiener diversity and simpson Dominance *** turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value *** firmum and Tectona grandis followed in terms of *** structural composition indicated higher number of individuals in the medium growth classes（41 to 〈 511 cm DBH and 16–20 m height ranges）,whereas *** was the only species that dominated most of the growth *** stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and *** study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of *** will also contribute to identifying threatened plants to undertake *** based conservation and sustainable management of the Fasiakhali Wildlife sanctuary.

关键词： species diversity structural composition Protected area Importance value index Cluster analysis

Cylindrical and spherical Electron-Acoustic shock Waves in Electron-Positron-Ion Plasmas with Nonextensive Electrons and Positrons

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Communications in Theoretical Physics 2015年第2期63卷 243-248页

作者： A.Rafat m.m.Rahman m.s.alam A.A.mamun Department of Physics Jahangirnagar University

Electron-acoustic shock waves(EAsWs) in an unmagnetized four-component plasma(containing hot electrons and positrons following the q-nonextensive distribution, cold mobile viscous electron fluid, and immobile positive ions) are studied in nonplanar(cylindrical and spherical) geometry. With the help of the reductive perturbation method,the modified Burgers equation is derived. Analytically, the effects of nonplanar geometry, nonextensivity, relative number density and temperature ratios, and cold electron kinematic viscosity on the basic properties(viz. amplitude, width,speed, etc.) of EAsWs are discussed. It is examined that the EAsWs in nonplanar geometry significantly differ from those in planar geometry. The results of this investigation can be helpful in understanding the nonlinear features of EAsWs in various astrophysical plasmas.

关键词：天体等离子体正电子圆柱形正负电子对球形 Burgers方程震波几何形状

Numerical simulations of Hydromagnetic mixed Convection Flow of Nanofluids inside a Triangular Cavity on the Basis of a Two-Component Nonhomogeneous mathematical model

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Fluid Dynamics & materials Processing 2021年第1期17卷 1-20页

作者： Khadija A.Al-Hassani m.s.alam m.m.Rahman Department of mathematics College of ScienceSultan Qaboos UniversityMuscatOman Department of mathematics Jagannath UniversityDhakaBangladesh

Nanofluids have enjoyed a widespread use in many technological applications due to their peculiar *** simulations are presented about the unsteady behavior of mixed convection of Fe_(3)O_(4)-water,Fe_(3)O_(4)-kerosene,Fe_(3)O_(4)-ethylene glycol,and Fe_(3)O_(4)-engine oil nanofluids inside a lid-driven triangular *** particular,a two-component non-homogeneous nanofluid model is *** bottom wall of the enclosure is insulated,whereas the inclined wall is kept a constant(cold)temperature and various temperature laws are assumed for the vertical wall,namely:θ=1(Case 1),θ=Yð1YÞ(Case 2),andθ=sinð2-YÞ(Case 3).A tilted magnetic field of uniform strength is also present in the fluid *** a numerical point of view,the problem is addressed using the Galerkin weighted residual finite element *** role played by different parameters is assessed,discussed critically and interpreted from a physical *** find that a higher aspect ratio can produce an increase in the average Nusselt ***,the Fe_(3)O_(4)-EO and Fe_(3)O_(4)-H2O nanofluids provide the highest and smallest rate of heat transfer,respectively,for all the considered(three variants of)thermal boundary conditions.

关键词： Nanofluid mixed convection lid-driven triangular cavity finite element method

Pre-sowing treatments for improved germination and growth of two rare native species of Bangladesh

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Journal of Forestry Research 2018年第5期29卷 1277-1282页

作者： m.A.Hossain K.s.Islam N.Rajasree m.K.Hossain m.s.alam Institute of Forestry and Environmental sciences University of Chittagong

Pre-sowing treatments are expected to increase seed *** evaluates response to pre-sowing treatments and the growth performance of two native and rare tree species,Garuga pinnata *** Vitex glabrata *** hard seed coats were treated by rubbing with sand paper,nail clipping,and immersion in water and acid（H_2sO_4）.Results indicate that *** showed a 90% germination rate and 30% germination energy when seed coats were nicked with a nail *** with sand paper was the best pre-sowing treatment for ***,resulting a 80% germination rate and 30% germination *** and *** seedlings from seeds soaked 24h in water resulted in maximum heights and collar *** were significantly higher（at p〈0.05） than those of other *** results indicate that scarification or nicking of seeds may have some negative impacts on seedling ***,it is difficult to recommend a pre-sowing treatment of seeds for achieving both maximum germination and good early seedling growth.

关键词： Germination Early seedling growth Height Native species Garuga pinnata Vitex glabrata

Effect of Fluidic Diode on Performance of Unidirectional Impulse Turbine

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Journal of Thermal science 2024年第3期33卷 807-814页

作者： DODDAmANI Hithaish ABDUs samad mANABU Takao sHINYA Okuhara m m AsHRAFUL alam Department of Ocean Engineering Indian Institute of Technology MadrasChennai600036India Department of mechanical Engineering National Institute of TechnologyMatsue CollegeShimane6908518Japan Center of support Practical Education National Institute of TechnologyMatsue CollegeShimane6908518Japan Department of Transportation Engineering Osaka Sangyo UniversityDaito5748530Japan

A pair of unidirectional turbines(UT)can operate in oscillatory airflow without additional ***,this arrangement suffers from poor flow rectification.A fluidic diode(FD)offers variable hydrodynamic resistance based on the flow direction,and this can be coupled with UT to improve flow *** this work,a numerical investigation on the effect of FD with UT is presented using the commercial fluid dynamics software ANsYs Fluent 16.1 with k-ωssT turbulence closure *** domains of UT and FD are numerically validated individually with experimental ***,both are coupled to obtain the combined effect,and these results are compared with the analytical *** was observed that coupling FD with UT improved the unit's performance at the lower flow coefficient(s performance decreased as the flow coefficient *** to the diode's presence,fluid leaving the turbine experiences higher resistance at a higher flow coefficient,which decreases the overall performance of the combined unit.

关键词： wave energy oscillating water column unidirectional impulse turbine fluidic diode flow rectification

Neural network study of the nuclear ground-state spin distribution within a random interaction ensemble

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Nuclear science and Techniques 2024年第3期35卷 216-227页

作者： Deng Liu alam Noor A Zhen-Zhen Qin Yang Lei school of mathematics and Physics Southwest University of Science and TechnologyMianyang 621010China school of Nuclear science and Technology Southwest University of Science and TechnologyMianyang 621010China

The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output *** quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the ***,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists.

关键词： Neural network Two-body random ensemble spin distribution of nuclear ground state

孟加拉吉大港市藤家具企业的经济效益分析(英文)

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Journal of Forestry Research 2006年第2期17卷 153-156页

作者： m.alamgir m.A.R.Bhuiyan m.Jashimuddin m.s.alam Bangladesh Forest school Chittagong Bangladesh Institute of Forestry and Environmental sciences University of ChittagongChittagong-4331Bangladesh

采用分阶段抽样方式对大港市藤家具企业的经济效益进行调查。根据总投资将企业分为大型、中型和小型三类。大部分的企业(55%)已有40-50年的历史,仅有18.33%的企业历史超过50年。在小型和中型企业中,具有大学毕业文凭的企业家只占8.33%,... 详细信息

采用分阶段抽样方式对大港市藤家具企业的经济效益进行调查。根据总投资将企业分为大型、中型和小型三类。大部分的企业(55%)已有40-50年的历史,仅有18.33%的企业历史超过50年。在小型和中型企业中,具有大学毕业文凭的企业家只占8.33%,而大型企业的大学毕业者占18.33%。大部分企业(45%)属于小型企业,66.67%的工人经过技术培训。7种商品是藤类制品并有16种尺寸,如沙发(45cm×45cm,50cm×50cm and55cm×55cm),配套餐桌(4把椅子,1个桌子,或6把椅子1个桌子),床(1m×2m,1.3m×2.3m and1.5m×2.3m),椅子(45cm×45cm and50cm×50cm),摇椅(大、中、小)等。在所有大型、中型和小型企业中,以生产椅子最多,床最少。大型藤家具企业的总净收益和收益造价比(1:16)最高。图2表3参21。

关键词：孟加拉藤家具企业净收益收益造价比

The link between intracellular calcium signaling and exosomal PD-L1 in cancer progression and immunotherapy

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Genes & Diseases 2024年第1期11卷 321-334页

作者： md Rakibul alam md mizanur Rahman Zhiguo Li Department of Toxicology and Cancer Biology College of MedicineUniversity of KentuckyLexingtonKY 40506USA Department of medicine(Nephrology) Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlberta T6E2H7Canada

Exosomes are small membrane vesicles containing microRNA,RNA,DNA fragments,and proteins that are transferred from donor cells to recipient *** cells release exo-somes to reprogram the factors associated with the tumor microenvironment(TmE)causing tu-mor metastasis and immune *** evidence revealed that cancer cell-derived exosomes carry immune inhibitory molecule program death ligand 1(PD-L1)that binds with re-ceptor program death protein 1(PD-1)and promote tumor progression by escaping immune ***,some FDA-approved monoclonal antibodies are clinicallyused for cancer treatment by blocking PD-1/PD-L1 *** notable treatment outcomes,some pa-tients show poor drug *** PD-L1 plays a vital role in lowering the treatment response,showing resistance to PD-1/PD-L1 blockage therapy through recapitulating the ef-fect of cell surface *** enhance therapeutic response,inhibition of exosomal PD-L1 is *** signaling is the central regulator of tumorigenesis and can regulate exosome biogenesis and secretion by modulating Rab GTPase family and membrane fusion ***-mune checkpoints are also connected with calcium signaling and calcium channel blockers like amlodipine,nifedipine,lercanidipine,diltiazem,and verapamil were also reported to suppress cellular PD-L1 ***,to enhance the PD-1/PD-L1 blockage therapy response,the reduction of exosomal PD-L1 secretion from cancer cells is in our therapeutic *** this review,we proposed a therapeutic strategy by targeting calcium signaling to inhibit the expression of PD-L1-containing exosome levels that could reduce the anti-PD-1/PD-L1 therapy resistance and increase the patient's drug response rate.

关键词： Calcium signaling CD8^(+)T cells Exosomal PD-L1 Exosomes biogenesis Immunosuppression Immunotherapy